Tanning.



UNITED STATES PATENT OFFICE.

EDMUND. STIASliI'Y, OF HEADINGLY, ENGLAND, .AND OTTO SCHMIDT, QFLUDWIGSHAFEN- ON-THE-RHINE, GERMANY, ASSIG NORS TO BADISCHE ANILIN &SODA FABRIK, 0F LUDWIGSHAFEN-ON-THE-RHINE, GERMANY, A CORPORATION.

Patented Oct. 31, 191?.

TANNING.

1 203,069. Specification of Letters Patent.

No Drawing. Application filed March 23, 1914.

To all whom it may concern Be it known that we, EDMUND STIASNY and OrroScrunor, citizens of the Austro- Hungarian and German Empires,respectively, residing at Headingly, Leeds, England, andLudwigshafen-on-the-Rhine, Germany, have ini'ented new and useful11nprovements in Tanning, of which the following is a specification.

Ve have discovered that we can obtain a. good leather by treating hideswith a class of compounds which have hitherto not been employed for thispurpose. This new class ofcompounds is characterized by the followingproperties: All the bodies, which can be used according to the presentinvention, are water-soluble aromatic compounds of a non-crystallinecharacter, which are practicall, compounds and from sulfone groups,contain hydroxyl in the molecule, but not more than one hydroxyl groupin each nucleus, contain at least two aromatic nuclei combined in themolecule by at least one atomic group or vpolyvalent atom, contains atleast one acid salt-forming group besides the hydroxyl group, and in theform of their free acids are capable of precipitating glue, or

gelatin, from solutions thereof.

The following are examples of how this inventioninay be performed, butthe invention is not confined to these examples. The parts are byWeight. 7 v Example 1: Neutralize, by means of caus tic soda, aconcentratedsolution of thepr'odnot obtained by acting with sulfur-mono:chlorid (S 01 0n sulfonated cresol and then dilute with water till thesolution is of about five per cent. strength. Then tan, in the usualway, with this preparation. The leather obtained is not colored, butotherwise it resembles very closely leather pre pared with the aid ofvegetable tanning agents. The tanning agent mentioned fill. this examplcan be prepared, for in; stance, as follows: Heat 239 parts of cresolwith261 arts of concentrated sul= furic acid till su lfo'nation isfinished, then cool the mass and pour into it slowly, drop by drop, atordinary temperature, 'and while stirring well, 150 parts of sulfurmonochlorid (S Cl When hydrochloric acid ceases free fromdiphenyl-methane Serial No. 826,790.

to be evolved, pour the mass onto ice, dilute the reaction liquid withwater, and boil until the sulfur has separated out. Then filter 0d thesulfur. The solution can, if necessary, be evaporated down.

Example 2: Dissolve 100 parts of the body termed thionaphthol sulfonicacid B (obtainable according to the specification of German Patent N 0.50,077 and to which we attribute the constitution s CIO fifSQSH-OHomutsomou or:

S C1o :lsSOaH.OPl

1OH5SO3EL0H) in 2000 parts of water, and use this solution for tanningas directed.

Example 3: Warm together, for ten hours, at 1 009 0., 94 parts ofphenol, 100 parts of 98% sulfuric acid and 46 parts of glycerin. Allowthe mass to cool, and pour it onto ice, and filter it. The filtratecontains an easily soluble, and strongly acid, body containing phenolichydroxyl and sulfon1c acid groups. Then nearly neutralize the solutionwith caustic soda, and dilute with water until a solution of 2 Baum isobtained. Then introduce the well-limed and hated skins and proceed withthe tanning, gradually raising the strength of the solution to 4 Baum.In this way a soft, full, coarse-grained leather is obtained. Productsobtained by the actionof glycerin on phenol sulfonic acid can also beused in a similar manner for tanning purposes.

Examples: Prepare asolution of the urea of 2-amlno-5 naphthol T'sulfonic acid and employ this solution for tanning purposes,

whereupon a hard leather is obtained with bined in the molecule by atleast one atomic group or polyvalent atom, and which contains at leastone acid salt-forming group besides the hydroxyl group, and which, inthe form of its free acid, is capable of precipitating glue and gelatinfrom solutions thereof.

2. The process of tanning which consists in treating hides with asoluble aromatic compound, obtainable by treating sulfonated cresol withsulfur mono-chlorid.

In testimony whereof we have hereunto set our hands in the presence oftwo subscribing witnesses.

